Multiaxial press fabric having shaped yarns

ABSTRACT

A multiaxial press fabric includes a base fabric and a plurality of layers of staple fiber material attached to the base fabric. The base fabric has at least one layer assembled by spirally winding a woven fabric strip, and takes the form of an endless loop. Because of the spiral winding, the yarns of the woven fabric strip lie in directions different from the machine- and cross-machine directions of the base fabric, giving the base fabric multiaxial characteristics. The woven fabric strip includes, in at least one of its lengthwise and crosswise directions, shaped yarns, which are either hollow yarns or yarns having a non-circular cross section.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the papermaking arts. Morespecifically, the present invention relates to press fabrics for thepress section of a paper machine.

2. Description of the Prior Art

During the papermaking process, a cellulosic fibrous web is formed bydepositing a fibrous slurry, that is, an aqueous dispersion of cellulosefibers, onto a moving forming fabric in the forming section of a papermachine. A large amount of water is drained from the slurry through theforming fabric, leaving the cellulosic fibrous web on the surface of theforming fabric.

The newly formed cellulosic fibrous web proceeds from the formingsection to a press section, which includes a series of press nips. Thecellulosic fibrous web passes through the press nips supported by apress fabric, or, as is often the case, between two such press fabrics.In the press nips, the cellulosic fibrous web is subjected tocompressive forces which squeeze water therefrom, and which adhere thecellulosic fibers in the web to one another to turn the cellulosicfibrous web into a paper sheet. The water is accepted by the pressfabric or fabrics and, ideally, does not return to the paper sheet.

The paper sheet finally proceeds to a dryer section, which includes atleast one series of rotatable dryer drums or cylinders, which areinternally heated by steam. The newly formed paper sheet is directed ina serpentine path sequentially around each in the series of drums by adryer fabric, which holds the paper sheet closely against the surfacesof the drums. The heated drums reduce the water content of the papersheet to a desirable level through evaporation.

It should be appreciated that the forming, press and dryer fabrics alltake the form of endless loops on the paper machine and function in themanner of conveyors. It should further be appreciated that papermanufacture is a continuous process which proceeds at considerablespeeds. That is to say, the fibrous slurry is continuously depositedonto the forming fabric in the forming section, while a newlymanufactured paper sheet is continuously wound onto rolls after it exitsfrom the dryer section.

The present invention relates specifically to the press fabrics used inthe press section. Press fabrics play a critical role during the papermanufacturing process. One of their functions, as implied above, is tosupport and to carry the paper product being manufactured through thepress nips.

Press fabrics also participate in the finishing of the surface of thepaper sheet. That is, press fabrics are designed to have smooth surfacesand uniformly resilient structures, so that, in the course of passingthrough the press nips, a smooth, mark-free surface is imparted to thepaper.

Perhaps most importantly, the press fabrics accept the large quantitiesof water extracted from the wet paper in the press nip. In order to fillthis function, there literally must be space, commonly referred to asvoid volume, within the press fabric for the water to go, and the fabricmust have adequate permeability to water for its entire useful life.Finally, press fabrics must be able to prevent the water accepted fromthe wet paper from returning to and rewetting the paper upon exit fromthe press nip.

Contemporary press fabrics are produced in a wide variety of stylesdesigned to meet the requirements of the paper machines on which theyare installed for the paper grades being manufactured. Generally, theycomprise a woven base fabric into which has been needled a batt of fine,nonwoven fibrous material. The base fabrics may be woven frommonofilament, plied monofilament, multifilament or plied multifilamentyarns, and may be single-layered, multi-layered or laminated. The yarnsare typically extruded from any one of the synthetic polymeric resins,such as polyamide and polyester resins, used for this purpose by thoseof ordinary skill in the paper machine clothing arts.

The woven base fabrics themselves take many different forms. Forexample, they may be woven endless, or flat woven and subsequentlyrendered into endless form with a woven seam. Alternatively, they may beproduced by a process commonly known as modified endless weaving,wherein the widthwise edges of the base fabric are provided with seamingloops using the machine-direction (MD) yarns thereof. In this process,the MD yarns weave continuously back-and-forth between the widthwiseedges of the fabric, at each edge turning back and forming a seamingloop. A base fabric produced in this fashion is placed into endless formduring installation on a papermachine, and for this reason is referredto as an on-machine-seamable fabric. To place such a fabric into endlessform, the two widthwise edges are brought together, the seaming loops atthe two edges are interdigitated with one another, and a seaming pin orpintle is directed through the passage formed by the interdigitatedseaming loops.

Further, the woven base fabrics may be laminated by placing one basefabric within the endless loop formed by another, and by needling astaple fiber batt through both base fabrics to join them to one another.One or both woven base fabrics may be of the on-machine-seamable type.

In any event, the woven base fabrics are in the form of endless loops,or are seamable into such forms, having a specific length, measuredlongitudinally therearound, and a specific width, measured transverselythereacross. Because paper machine configurations vary widely, papermachine clothing manufacturers are required to produce press fabrics,and other paper machine clothing, to the dimensions required to fitparticular positions in the paper machines of their customers. Needlessto say, this requirement makes it difficult to streamline themanufacturing process, as each press fabric must typically be made toorder.

In response to this need to produce press fabrics in a variety oflengths and widths more quickly and efficiently, press fabrics have beenproduced in recent years using a spiral technique disclosed in commonlyassigned U.S. Pat. No. 5,360,656 to Rexfelt et al., the teachings ofwhich are incorporated herein by reference.

U.S. Pat. No. 5,360,656 shows a press fabric comprising a base fabrichaving one or more layers of staple fiber material needled thereinto.The base fabric comprises at least one layer composed of a spirallywound strip of woven fabric having a width which is smaller than thewidth of the base fabric. The base fabric is endless in thelongitudinal, or machine, direction. Lengthwise threads of the spirallywound strip make an angle with the longitudinal direction of the pressfabric. The strip of woven fabric may be flat-woven on a loom which isnarrower than those typically used in the production of paper machineclothing.

The base fabric comprises a plurality of spirally wound and joined turnsof the relatively narrow woven fabric strip. The fabric strip is wovenfrom lengthwise (warp) and crosswise (filling) yarns. Adjacent turns ofthe spirally wound fabric strip may be abutted against one another, andthe helically continuous seam so produced may be closed by sewing,stitching, melting or welding. Alternatively, adjacent longitudinal edgeportions of adjoining spiral turns may be arranged overlappingly, solong as the edges have a reduced thickness, so as not to give rise to anincreased thickness in the area of the overlap. Further, the spacingbetween lengthwise yarns may be increased at the edges of the strip, sothat, when adjoining spiral turns are arranged overlappingly, there maybe an unchanged spacing between lengthwise threads in the area of theoverlap.

In any case, a woven base fabric, taking the form of an endless loop andhaving an inner surface, a longitudinal (machine) direction and atransverse (cross-machine)) direction, is the result. The lateral edgesof the woven base fabric are then trimmed to render them parallel to itslongitudinal (machine) direction. The angle between the machinedirection of the woven base fabric and the helically continuous seam maybe relatively small, that is, typically less than 10°. By the sametoken, the lengthwise (warp) yarns of the woven fabric strip make thesame relatively small angle with the longitudinal (machine) direction ofthe woven base fabric. Similarly, the crosswise (filling) yarns of thewoven fabric strip, being perpendicular to the lengthwise (warp) yarns,make the same relatively small angle with the transverse (cross-machine)direction of the woven base fabric. In short, neither the lengthwise(warp) nor the crosswise (filling) yarns of the woven fabric strip alignwith the longitudinal (machine) or transverse (cross-machine) directionsof the woven base fabric.

In the method shown in U.S. Pat. No. 5,360,656, the woven fabric stripis wound around two parallel rolls to assemble the woven base fabric. Itwill be recognized that endless base fabrics in a variety of widths andlengths may be provided by spirally winding a relatively narrow piece ofwoven fabric strip around the two parallel rolls, the length of aparticular endless base fabric being determined by the length of eachspiral turn of the woven fabric strip, and the width being determined bythe number of spiral turns of the woven fabric strip. The priornecessity of weaving complete base fabrics of specified lengths andwidths to order may thereby be avoided. Instead, a loom as narrow as 20inches (0.5 meters) could be used to produce a woven fabric strip, but,for reasons of practicality, a conventional textile loom having a widthof from 40 to 60 inches (1.0 to 1.5 meters) may be preferred.

U.S. Pat. No. 5,360,656 also shows a press fabric comprising a basefabric having two layers, each composed of a spirally wound strip ofwoven fabric. Both layers take the form of an endless loop, one beinginside the endless loop formed by the other. Preferably, the spirallywound strip of woven fabric in one layer spirals in a direction oppositeto that of the strip of woven fabric in the other layer. That is to say,more specifically, the spirally wound strip in one layer defines aright-handed spiral, while that in the other layer defines a left-handedspiral. In such a two-layer, laminated base fabric, the lengthwise(warp) yarns of the woven fabric strip in each of the two layers makerelatively small angles with the longitudinal (machine) direction of thewoven base fabric, and the lengthwise (warp) yarns of the woven fabricstrip in one layer make an angle with the lengthwise (warp) yarns of thewoven fabric strip in the other layer. Similarly, the crosswise(filling) yarns of the woven fabric strip in each of the two layers makerelatively small angles with the transverse (cross-machine) direction ofthe woven base fabric, and the crosswise (filling) yarns of the wovenfabric strip in one layer make an angle with the crosswise (filling)yarns of the woven fabric strip in the other layer. In short, neitherthe lengthwise (warp) nor the crosswise (filling) yarns of the wovenfabric strip in either layer align with the longitudinal (machine) ortransverse (cross-machine) directions of the base fabric. Further,neither the lengthwise (warp) nor the crosswise (filling) yarns of thewoven fabric strip in either layer align with those of the other.

As a consequence, the base fabrics shown in U.S. Pat. No. 5,360,656 haveno defined machine- or cross-machine-direction yarns. Instead, the yarnsystems lie in directions at oblique angles to the machine andcross-machine directions. A press fabric having such a base fabric maybe referred to as a multiaxial press fabric. Whereas the standard pressfabrics of the prior art have three axes: one in the machine direction(MD), one in the cross-machine direction (CD), and one in theZ-direction, which is through the thickness of the fabric, a multiaxialpress fabric has not only these three axes, but also has at least twomore axes defined by the directions of the yarn systems in its spirallywound layer or layers. Moreover, there are multiple flow paths in theZ-direction of a multiaxial press fabric. As a consequence, a multiaxialpress fabric has at least five axes. Because of its multiaxialstructure, a multiaxial press fabric having more than one layer exhibitssuperior resistance to nesting and/or to collapse in response tocompression in a press nip during the papermaking process as compared toone having base fabric layers whose yarn systems are parallel to oneanother.

The present invention is an improved multiaxial press fabric having abase fabric of the foregoing type. The base fabric, or, moreparticularly, the strip of woven fabric from which the base fabric isassembled, includes shaped yarns in at least one of its lengthwise(warp) and crosswise (filling) directions. The shaped yarns may beeither hollow yarns or yarns of non-circular cross section.

SUMMARY OF THE INVENTION

In its broadest form, the present multiaxial press fabric for the presssection of a paper machine comprises a base fabric having at least onelayer formed by spirally winding a fabric strip. The fabric strip iswoven from lengthwise yarns and crosswise yarns.

At least one of the lengthwise yarns and crosswise yarns are shapedyarns. The shaped yarns are either hollow yarns or yarns of anon-circular cross section. The non-circular cross section may be of asubstantially rectangular shape or may have a plurality of lobes.

The fabric strip has a first lateral edge and a second lateral edge, andis spirally wound in a plurality of contiguous turns wherein the firstlateral edge in a turn of the fabric strip abuts the second lateral edgeof an adjacent turn thereof. A helically continuous seam separatingadjacent turns of the fabric strip is thereby formed. The helicallycontinuous seam is closed by attaching abutting first and second lateraledges of the fabric strip to one another. In this manner, a base fabricin the form of an endless loop having a machine direction, across-machine direction, an inner surface and an outer surface isprovided.

The base fabric may comprise one or more additional layers formed byspirally winding fabric strips, which are woven from lengthwise yarnsand crosswise yarns. As above, at least one of the lengthwise yarns andthe crosswise yarns may be shaped yarns.

The additional fabric strip or strips also have first lateral edges andsecond lateral edges, and are spirally wound in a plurality ofcontiguous turns wherein the first lateral edge in a turn of eachadditional fabric strip abuts the second lateral edge of an adjacentturn thereof. Helically continuous seams separating adjacent turns ofthe additional fabric strips are thereby formed. The helicallycontinuous seams are closed by attaching abutting first and secondlateral edges of each additional fabric strip to one another. In thismanner, one or more additional layers in the form of endless loopshaving a machine direction, a cross-machine direction, an inner surfaceand an outer surface are provided. Preferably, at least some of theadditional fabric strips are spirally wound in a direction opposite tothat in which the first fabric strip is spirally wound. The endlessloops formed by the additional layer or layers are disposed around theendless loop formed by the first layer.

A plurality of layers of staple fiber material is attached to one orboth of the inner and outer surfaces of the base fabric. At the sametime, where the base fabric includes more than one layer, the layers areattached to one another by individual fibers of the staple fibermaterial needled therethrough.

The present invention will now be described in more complete detail withfrequent reference being made to the figures identified below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic top plan view illustrating a method formanufacturing one of the layers of the base fabric of the multiaxialpress fabric of the present invention;

FIG. 2 is a cross-sectional view taken as indicated by line 2—2 in FIG.1;

FIG. 3 is a cross-sectional view taken as indicated by line 3—3 in FIG.2;

FIG. 4 is a top plan view of a finished layer of the base fabric;

FIG. 5 is a top plan view of a two-layer, laminated base fabric for themultiaxial press fabric of the present invention;

FIG. 6 is a perspective view of the multiaxial press fabric of thepresent invention;

FIG. 7 is a cross-sectional view of a shaped yarn having a trilobalcross section;

FIG. 8 is a cross-sectional view of a shaped yarn having a quadrilobalcross section; and

FIG. 9 is a cross-sectional view of a hollow yarn.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the several figures, FIG. 1 is a schematic top planview illustrating a method for manufacturing one of the layers of thebase fabric of the multiaxial press fabric of the present invention. Themethod may be practiced using an apparatus 10 comprising a first roll 12and a second roll 14, which are parallel to one another and which may berotated in the directions indicated by the arrows. A woven fabric strip16 is wound from a stock roll 18 around the first roll 12 and the secondroll 14 in a continuous spiral. It will be recognized that it may benecessary to translate the stock roll 18 at a suitable rate along secondroll 14 (to the right in FIG. 1) as the fabric strip 16 is being woundaround the rolls 12,14.

The first roll 12 and the second roll 14 are separated by a distance D,which is determined with reference to the total length required for thebase fabric layer being manufactured, the total length being measuredlongitudinally (in the machine direction) about the endless-loop form ofthe layer. Woven fabric strip 16, having a width w, is spirally woundonto the first and second rolls 12,14 in a plurality of turns from stockroll 18, which may be translated along the second rolls 14 in the courseof the winding. Successive turns of the fabric strip 16 are abuttedagainst one another and are attached to one another along helicallycontinuous seam 20 by sewing, stitching, melting or welding to producebase fabric layer 22 as shown in FIG. 4. When a sufficient number ofturns of the fabric strip 16 have been made to produce layer 22 in thedesired width W, that width being measured transversely (in thecross-machine direction) across the endless-loop form of the layer 22,the spiral winding is concluded. The base fabric layer 22 so obtainedhas an inner surface, an outer surface, a machine direction and across-machine direction. Initially, the lateral edges of the base fabriclayer 22, it will be apparent, will not be parallel to the machinedirection thereof, and must be trimmed along lines 24 to provide thelayer 22 with the desired width W, and with two lateral edges parallelto the machine direction of its endless-loop form.

Fabric strip 16 is woven from lengthwise yarns and crosswise yarns.Either the lengthwise yarns or the crosswise yarns, or both thelengthwise yarns and the crosswise yarns, are shaped yarns of one of thevarieties to be described below. Fabric strip 16 may also includemonofilament, plied monofilament or multifilament yarns. Both theselatter yarns and the shaped yarns are extruded from a syntheticpolymeric resin, such as polyester or polyamide. Fabric strip 16 may bewoven in the same manner as are other fabrics used in the papermakingprocess, and may be of a single- or multi-layer weave. After weaving,the fabric may be heatset in a conventional manner prior to interimstorage on stock roll 18.

Alternatively, fabric strip 16 may be woven and heatset in aconventional manner, and fed directly to apparatus 10 from a heatsetunit without interim storage on a stock roll 18. It may also be possibleto eliminate heatsetting with the proper material selection and productconstruction (weave, yarn sizes and counts). In such a situation, fabricstrip 16 would be fed to the apparatus 10 from a weaving loom withoutinterim storage on a stock roll 18.

FIG. 2 is a cross section of a fabric strip 16 taken as indicated byline 2—2 in FIG. 1. It comprises lengthwise yarns 26 and crosswise yarns28, interwoven in a 7-shed, single-layer weave. Crosswise yarns 28 arerepresented as monofilaments of circular cross section, although, itshould be understood, they may be either plied monofilament yarns ormultifilament yarns, or shaped yarns of one of the varieties to bedescribed below.

FIG. 3 is a cross section taken as indicated by line 3—3 in FIG. 2.Lengthwise yarns 26, now seen in cross section, are shaped yarns; thatis, more specifically, lengthwise yarns 26 are monofilament yarns ofsubstantially rectangular cross direction. Perforations 42 pass throughthe lengthwise yarns 26. Together with the illustrated 7-shed weavepattern, these flat monofilament yarns give the fabric strip anextremely smooth surface on the side (top in the figure) on which thelengthwise yarns 26 make long floats over the crosswise yarns 28. Itshould be understood, however, that fabric strip 16 may be wovenaccording to any of the weave patterns commonly used to weave papermachine clothing.

Because the fabric strip 16 is spirally wound to assemble base fabriclayer 22, lengthwise yarns 26 and crosswise yarns 28 do not align withthe machine and cross-machine directions, respectively, of the layer 22.Rather, the lengthwise yarns 26 make a slight angle, θ, whose magnitudeis a measure of the pitch of the spiral windings of the fabric strip 16,with respect to the machine direction of the layer 22, as suggested bythe top plan view thereof shown in FIG. 4. This angle, as previouslynoted, is typically less than 10°. Because the crosswise yarns 28 of thefabric strip 16 generally cross the lengthwise yarns 26 at a 90° angle,the crosswise yarns 28 make the same slight angle, θ, with respect tothe cross-machine direction of the layer 22.

Woven fabric strip 16 has a first lateral edge 30 and a second lateraledge 32 which together define the width of the body of the woven fabricstrip 16. As the fabric strip 16 is being spirally wound onto the firstand second rolls 12, 14, the first lateral edge 30 of each turn isabutted against the second lateral edge 32 of the immediately precedingturn and attached thereto.

In a preferred method, if desired, a second base fabric layer for themultiaxial press fabric of the present invention may be provided on topof base fabric layer 22 before removing base fabric layer 22 fromapparatus 10. The second base fabric layer 34 may be fashioned in thesame manner as is described above. Preferably, second base fabric layer34 is manufactured to spiral in a direction opposite to that of basefabric layer 22 by starting at the right side of second roll 14 in FIG.1, rather than at the left side, as was the case for the manufacture ofbase fabric layer 22, and by translating stock roll 18 at a suitablerate to the left along second roll 14 as the fabric strip 16 is beingwound around the rolls 12,14. It will be appreciated that fabric strip16 will have to be wound in a sufficient number of turns to completelycover base fabric layer 22, and that the lateral edges of second basefabric layer 34 will have to be trimmed to be rendered parallel to themachine direction and to conform to those of base fabric 22. The resultis shown in FIG. 5, where helically continuous seam 20 of base fabriclayer 22 is shown as a dashed line. Additional layers, spiralling ineither direction, may be provided in the same manner.

The two-layer, laminated base fabric 36 shown in FIG. 5 thereforecomprises a second base fabric layer 34 which overlies the first basefabric layer 22. The lengthwise (warp) yarns 26 in fabric strip 16 inboth layers 22,34 make relatively small angles with respect to themachine direction (MD) of base fabric 36, and, because first layer 22and second layer 34 spiral in opposite directions, cross each other at arelatively small angle that is equal to the sum of the angles each makeswith the machine direction. Similarly, the crosswise (filling) yarns 28in the fabric strip 16 in both layers 22,34 make small angles withrespect to the cross-machine direction (CD) of base fabric 36, and crosseach other at a relatively small angle that is equal to the sum of theangles each makes with the cross-machine direction. As a consequence,the two-layer, laminated base fabric 36 has no defined machine- orcross-machine-direction yarns. Instead, lengthwise (warp) yarns 26 andcrosswise (filling) yarns 28 of the first and second layers 22,34 lie infour different directions at oblique angles to the machine andcross-machine directions. For this reason, base fabric 36 is consideredto be multiaxial.

FIG. 6 is a perspective review of a multiaxial press fabric 46 of thepresent invention. Press fabric 46 is in the form of an endless loophaving an inner surface 48 and an outer surface 50, and comprises basefabric 36.

The outer surface 50 of multiaxial press fabric 46 has a plurality oflayers of staple fiber material attached thereto by needling. Theneedling of the layers of staple fiber material into the outer surface50 of the press fabric 46 also attaches the first and second layers 22,34 of the base fabric 36 to one another, as the needling drivesindividual fibers of the staple fiber material into and through theoverlying first and second layers 22, 34. The staple fiber material maybe of polyamide, polyester or any of the other varieties of staple fiberused by those of ordinary skill in the art to manufacture paper machineclothing. In general, one or both of the inner and outer surfaces of thepress fabric have a plurality of layers of staple fiber materialattached thereto by needling.

Returning now to the shaped yarns included in the strip of woven fabricused to produce the multiaxial press fabric of the present invention,the shaped yarns are included in at least one of the lengthwise (warp)and crosswise (filling) directions of the fabric strip 16. The shapedyarns may be monofilament yarns of substantially rectangular crosssection, as was the case with the lengthwise yarns 26 seen above in FIG.3.

The shaped yarns of substantially rectangular cross section may, forexample, have a width in the range from 0.25 mm to 0.50 mm, and athickness in the range from 0.12 mm to 0.25 mm. Shaped yarns having awidth greater than 0.50 mm may be used; where this is the case, theshaped yarns may be perforated to permit water to pass therethrough aswell as around the yarns.

As implied above, shaped yarns of rectangular cross section provide anextended yarn surface for maximum sheet pressure uniformity within thepress nip. The yarn surface, being elongated, will wear at a reducedrate, thereby extending the useful life of the fabric. An additionaladvantage of the use of these yarns is that they make the press fabricthinner than would be the case if yarns of circular cross section wereused. This lower thickness, increased sheet pressure uniformity, and theincompressible nature of a multiaxial fabric of more than one layer makethe multiaxial fabric especially useful in presses of the long nip shoepress type having a grooved shoe press belt.

The shaped yarns may alternatively be of trilobal cross section, asshown in FIG. 7, or of quadrilobal cross section, as shown in FIG. 8.FIG. 7 is a cross-sectional view of a monofilament 60 having a trilobalcross section. The cross-sectional view presented in FIG. 7 indicatesthe presence of three lobes 62. FIG. 8 is a cross-sectional view of amonofilament 70 having a quadrilobal cross section. The cross-sectionalview presented in FIG. 8 indicates the presence of four lobes 72. Shapedyarns of these two types provide fabric strip 16, and ultimately themultiaxial press fabrics manufactured therefrom, with additional voidvolume, permitting the fabrics to accept additional amounts of water ina press nip. These yarns of the trilobal and quadrilobal cross sectionmay have cross-sectional dimensions (or diameters) in the same ranges asthose expressed above for the yarns of substantially rectangular crosssection.

Further, the shaped yarns may be hollow yarns of circular or some othercross-sectional shape. FIG. 9 is a cross-sectional view of such a hollowyarn 80, which may have a diameter in the range from 0.020 mm to 0.050mm. The presence of this kind of yarn in either direction in the fabricstrip will allow the multiaxial press fabric 46 to compress in a pressnip. In some applications, such compressibility is required to assistthe water removal process.

Modifications to the multiaxial press fabric of the present inventionwould be obvious to those of ordinary skill in the art, but would notbring the invention so modified beyond the scope of the appended claims.For example, the base fabric thereof may comprise, in addition to one ormore spirally wound layers, one or more layers of standard base fabric.That is to say, one or more additional layers may be formed by fabricshaving machine- and cross-machine direction yarns and produced bytechniques well-known to those of ordinary skill in the art. Such afabric may be woven endless in the dimensions required for the papermachine for which it is intended, or flat woven and subsequentlyrendered into endless form with a woven seam. It may also be produced bya modified endless weaving technique to be on-machine-seamable.Laminated fabrics, having one or more standard base fabric layers, mayalso be used.

What is claimed is:
 1. A multiaxial press fabric for the press sectionof a paper machine, said multiaxial press fabric comprising: a basefabric, said base fabric having a first layer, said first layercomprising a first fabric strip, said first fabric strip being wovenfrom lengthwise and crosswise yarns wherein at least one of saidlengthwise and crosswise yarns are shaped yarns, said first fabric striphaving a first lateral edge and a second lateral edge, said first fabricstrip being spirally wound in a plurality of contiguous turns whereinsaid first lateral edge in a turn of said first fabric strip abuts saidsecond lateral edge of an adjacent turn thereof, thereby forming ahelically continuous seam separating adjacent turns of said first fabricstrip, said helically continuous seam being closed by attaching abuttingfirst and second lateral edges of said first fabric strip to oneanother, thereby providing said first layer and said base fabric in theform of an endless loop having a machine direction, a cross-machinedirection, an inner surface and an outer surface; and a plurality oflayers of staple fiber material attached to one of said inner and outersurfaces of said base fabric, wherein said shaped yarns are monofilamentyarns of a non-circular cross section, wherein said non-circular crosssection is of a substantially rectangular shape, and wherein said shapedyarns are perforated.
 2. A multiaxial press fabric as claimed in claim1, said base fabric further comprising a second layer, said second layercomprising a second fabric strip, said second fabric strip being wovenfrom lengthwise and crosswise yarns wherein at least one of saidlengthwise and crosswise yarns are shaped yarns, said second fabricstrip having a first lateral edge and a second lateral edge, said secondfabric strip being spirally wound in a plurality of contiguous turnswherein said first lateral edge in a turn of said second fabric stripabuts said second lateral edge of an adjacent turn thereof, therebyforming a helically continuous seam separating adjacent turns of saidsecond fabric strip, said helically continuous seam being closed byattaching abutting first and second lateral edges of said second fabricstrip to one another, thereby providing said second layer in the form ofan endless loop having a machine direction, a cross-machine direction,an inner surface and an outer surface, said endless loop formed by saidsecond layer being around said endless loop formed by said first layer.3. A multiaxial press fabric as claimed in claim 2 wherein said secondfabric strip is spirally wound in a direction opposite to that in whichsaid first fabric strip is spirally wound.
 4. A multiaxial press fabricas claimed in claim 1 wherein said base fabric further comprises astandard base fabric having machine-direction andcross-machine-direction yarns, said standard base fabric being in theform of an endless loop having a machine direction, a cross-machinedirection, an inner surface and an outer surface.
 5. A multiaxial pressfabric as claimed in claim 4 wherein said endless loop formed by saidstandard base fabric is within said endless loop formed by said firstlayer.
 6. A multiaxial press fabric as claimed in claim 4 wherein saidstandard base fabric is woven endless.
 7. A multiaxial press fabric asclaimed in claim 4 wherein said standard base fabric ison-machine-seamable.
 8. A multiaxial press fabric as claimed in claim 1wherein said first fabric strip is of a single-layer weave.
 9. Amultiaxial press fabric as claimed in claim 1 wherein said first fabricstrip is of a multi-layer weave.
 10. A multiaxial press fabric asclaimed in claim 1 wherein said lengthwise yarns and said crosswiseyarns of said first fabric strip are of a synthetic polymeric resin. 11.A multiaxial press fabric as claimed in claim 1 wherein said first layerof said base fabric has lateral edges trimmed in a direction parallel tosaid machine direction thereof.
 12. A multiaxial press fabric as claimedin claim 1 wherein said first fabric strip makes an angle of less than10° with respect to said machine direction of said first layer.
 13. Amultiaxial press fabric as claimed in claim 2 wherein said second fabricstrip is of a single-layer weave.
 14. A multiaxial press fabric asclaimed in claim 2 wherein said second fabric strip is of a multi-layerweave.
 15. A multiaxial press fabric as claimed in claim 2 wherein saidlengthwise yarns and said crosswise yarns of said second fabric stripare of a synthetic polymeric resin.
 16. A multiaxial press fabric asclaimed in claim 2 wherein said second layer of said base fabric haslateral edges trimmed in a direction parallel to said machine directionthereof.
 17. A multiaxial press fabric as claimed in claim 2 whereinsaid second fabric strip makes an angle of less than 10° with respect tosaid machine direction of said second layer.
 18. A multiaxial pressfabric as claimed in claim 4 wherein said standard base fabric is of asingle-layer weave.
 19. A multiaxial press fabric as claimed in claim 4wherein said standard base fabric is of a multi-layer weave.
 20. Amultiaxial press fabric as claimed in claim 4 wherein said standard basefabric is a laminated fabric.
 21. A multiaxial press fabric as claimedin claim 4 wherein said lengthwise yarns and said crosswise yarns ofsaid standard base fabric are of a synthetic resin.
 22. A multiaxialpress fabric as claimed in claim 1 further comprising a plurality oflayers of staple fiber material attached to both of said inner and outersurfaces of said base fabric.
 23. A multiaxial press fabric as claimedin claim 1 wherein said staple fiber material is of a polymeric resinmaterial.
 24. A multiaxial press fabric as claimed in claim 23 whereinsaid polymeric resin material is selected from the group consisting ofpolyamide and polyester resins.
 25. A multiaxial press fabric as claimedin claim 22 wherein said staple fiber material is of a polymeric resinmaterial.
 26. A multiaxial press fabric as claimed in claim 25 whereinsaid polymeric resin material is selected from the group consisting ofpolyamide and polyester resins.
 27. A multiaxial press fabric as claimedin claim 2 wherein said shaped yarns of said second layer aremonofilament yarns of a non-circular cross section.
 28. A multiaxialpress fabric as claimed in claim 27 wherein said non-circular crosssection of said shaped yarn of said second layer is of a substantiallyrectangular shape.
 29. A multiaxial press fabric as claimed in claim 27wherein said non-circular cross section has a plurality of lobes.
 30. Amultiaxial press fabric as claimed in claim 29 wherein said plurality isthree.
 31. A multiaxial press fabric as claimed in claim 29 wherein saidplurality is four.
 32. A multiaxial press fabric as claimed in claim 2wherein said shaped yarns of said second layer are hollow yarns.
 33. Amultiaxial press fabric as claimed in claim 28, wherein said shaped yarnof said second layer is perforated.